<?php

/*
 * This file is part of SwiftMailer.
 * (c) 2004-2009 Chris Corbyn
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

/**
 * Allows reading and writing of bytes to and from an array.
 *
 * @package    Swift
 * @subpackage ByteStream
 * @author     Chris Corbyn
 */
class Swift_ByteStream_ArrayByteStream implements Swift_InputByteStream, Swift_OutputByteStream
{
	/**
	 * The internal stack of bytes.
	 *
	 * @var string[]
	 */
	private $_array = array();

	/**
	 * The size of the stack
	 *
	 * @var integer
	 */
	private $_arraySize = 0;

	/**
	 * The internal pointer offset.
	 *
	 * @var integer
	 */
	private $_offset = 0;

	/**
	 * Bound streams.
	 *
	 * @var Swift_InputByteStream[]
	 */
	private $_mirrors = array();

	/**
	 * Create a new ArrayByteStream.
	 *
	 * If $stack is given the stream will be populated with the bytes it contains.
	 *
	 * @param mixed $stack of bytes in string or array form, optional
	 */
	public function __construct($stack = null)
	{
		if (is_array($stack)) {
			$this->_array = $stack;
			$this->_arraySize = count($stack);
		} elseif (is_string($stack)) {
			$this->write($stack);
		} else {
			$this->_array = array();
		}
	}

	/**
	 * Reads $length bytes from the stream into a string and moves the pointer
	 * through the stream by $length.
	 *
	 * If less bytes exist than are requested the
	 * remaining bytes are given instead. If no bytes are remaining at all, boolean
	 * false is returned.
	 *
	 * @param integer $length
	 *
	 * @return string
	 */
	public function read($length)
	{
		if ($this->_offset == $this->_arraySize) {
			return false;
		}

		// Don't use array slice
		$end = $length + $this->_offset;
		$end = $this->_arraySize < $end
			? $this->_arraySize
			: $end;
		$ret = '';
		for (; $this->_offset < $end; ++$this->_offset) {
			$ret .= $this->_array[$this->_offset];
		}

		return $ret;
	}

	/**
	 * Writes $bytes to the end of the stream.
	 *
	 * @param string $bytes
	 */
	public function write($bytes)
	{
		$to_add = str_split($bytes);
		foreach ($to_add as $value) {
			$this->_array[] = $value;
		}
		$this->_arraySize = count($this->_array);

		foreach ($this->_mirrors as $stream) {
			$stream->write($bytes);
		}
	}

	/**
	 * Not used.
	 */
	public function commit()
	{
	}

	/**
	 * Attach $is to this stream.
	 *
	 * The stream acts as an observer, receiving all data that is written.
	 * All {@link write()} and {@link flushBuffers()} operations will be mirrored.
	 *
	 * @param Swift_InputByteStream $is
	 */
	public function bind(Swift_InputByteStream $is)
	{
		$this->_mirrors[] = $is;
	}

	/**
	 * Remove an already bound stream.
	 *
	 * If $is is not bound, no errors will be raised.
	 * If the stream currently has any buffered data it will be written to $is
	 * before unbinding occurs.
	 *
	 * @param Swift_InputByteStream $is
	 */
	public function unbind(Swift_InputByteStream $is)
	{
		foreach ($this->_mirrors as $k => $stream) {
			if ($is === $stream) {
				unset($this->_mirrors[$k]);
			}
		}
	}

	/**
	 * Move the internal read pointer to $byteOffset in the stream.
	 *
	 * @param integer $byteOffset
	 *
	 * @return boolean
	 */
	public function setReadPointer($byteOffset)
	{
		if ($byteOffset > $this->_arraySize) {
			$byteOffset = $this->_arraySize;
		} elseif ($byteOffset < 0) {
			$byteOffset = 0;
		}

		$this->_offset = $byteOffset;
	}

	/**
	 * Flush the contents of the stream (empty it) and set the internal pointer
	 * to the beginning.
	 */
	public function flushBuffers()
	{
		$this->_offset = 0;
		$this->_array = array();
		$this->_arraySize = 0;

		foreach ($this->_mirrors as $stream) {
			$stream->flushBuffers();
		}
	}
}
